Figure 11h

Two Examples of the Onset of Atrial Fibrillation from Foci in a Right Inferior Pulmonary Vein and a Left Superior Vein.
The electrogram with the pulmonary vein spike is the terminal part of a two-component electrogram obtained during sinus rhythm. In the upper panel, a burst of five spikes (astericks) with a mean cycle length of 170msec induced continuous electrical activity in the right inferior pulmonary vein (RIPV), with coarse atrial fibrillation on the surface electrocardiogram. The coupling interval of the first spike was 265msec. In the bottom panel on the left,a sinus beat (with a terminal spike) was followed by an isolated atrial ectopic beat(asterick) at a coupling of 240msec. The electrogram of the ectopic beat characteristically shows temporal reversal, with the rapid deflection spike preceding the lower amplitude, slower far-field atrial activity. On the right, in the same patient, a train of spike discharges (astericks) at a cycle length of 160msec sets off atrial fibrillation. The spike discharges are also characterized by temporal reversal but exhibit a progressively prolonged conduction time to the atria. The coupling interval of the first spike on the right (240msec) is identical to that of the isolated ectopic beat on the left. LSPV denotes left superior pulmonary vein, and U unipolar left atrial activity.

.Reference:Haaissaguerre,M.,and others,Spontaneous Initiation of Atrial Fibrillation by Ectopic Beats Originating In The Pulmonary Veins,N.Engl.J.Med.1998:339;659-66